lmdb as a dependency

[ypuzikov]

lmdb module is missing in the Requirements section.

• Ubuntu Linux 16.04
• a conda virtual environment created with conda create -n py3.6 python=3.6 anaconda
• installed PyTorch via conda install pytorch torchvision cuda80 -c soumith
• run the command python main.py --dataset lsun --dataroot [lsun-train-folder] --cuda
• get the following:

...

ModuleNotFoundError: No module named 'lmdb'

[ypuzikov]

It's easily solved by conda install lmdb, but the update in README is needed, I believe.

[IlSLY]

anyway, even I install lmdv module, it cannot work in my PC.